Quick Take
- Slugs may look like they are fighting in videos seen online, but it is actually an intense mating ritual.
- Slugs can mate with anyone within their own species, as they have both male and female reproductive organs.
- Slugs have intense ways to compete in these encounters, including the use of “love darts” and a practice called apophallation.
Slugs don’t seem like the type of animals capable of duking it out. However, a funny Instagram post by @tiny.sanctuary shows what appears to be a fight between two particularly aggressive slugs. But it raises the question: can their movements actually be defined as fighting, or is the strange display something else entirely? Read on to learn more about why these slugs may engage in a so-called battle.
Slugs are hermaphrodites with both male and female reproductive organs, meaning they can mate with any other slug of the same species.
©CerberZero/Shutterstock.com
Why Slugs Fight
Slugs fighting is not something that you often hear about, and that’s because it’s not a common behavior. Rather than fighting over territory or food like other animals, slugs may simply appear to be “fighting” during their mating. Slugs are hermaphrodites, meaning each individual has both male and female reproductive organs. This often results in competition between two slugs over reproductive success. The slug “battle” seen in the video is more akin to an intense courtship that determines how mating will occur. The two animals are pushing at each other and twisting in weird angles while trying to bite each other. The duel looks strange and even funny, especially considering how slow they move.
Before any interaction, the slugs have to locate each other. By tracking the chemical signals in each other’s mucus, slugs follow the trails left behind as they move. Once they find each other, they begin crawling over one another and “fighting.” The fights can escalate even more through love darts, sharp calcium spikes that the slugs use to stab each other. When stabbed, the dart injects hormones that increase the chances of paternity for the slug that delivered it. Since the slugs are competing for genetic advantage, delivering the first poke is important. While utilizing hormone-laced “darts” is intense enough, slug mating rituals can become even more bizarre. In a bid to ensure mating success, slugs may engage in a practice called apophallation, during which they bite off either their own or their partner’s penis. So, while slugs don’t normally “fight” in the traditional offensive/defensive sense, they certainly engage in a specific form of extreme mating.
